Herbicide contamination and the potential impact to seagrass meadows in Hervey Bay, Queensland, Australia

Low concentrations of herbicides (up to 70 ng 1(-1)), chiefly diuron (up to 50 ng 1 (-1)) were detected in surface waters associated with inter-tidal seagrass meadows of Zostera muelleri in Hervey Bay, south-cast Queensland, Australia. Diuron and atrazine (up to 1. 1 ng g(-1) dry weight of sediment) were detected in the sediments of these seagrass meadows. Concentration of the herbicides diuron, simazine and atrazine increased in surface waters associated with seagrass meadows during moderate river flow events indicating herbicides were washed from the catchment to the marine environment. Maximum herbicide concentration (sum of eight herbicides) in the Mary River during a moderate river flow event was 4260 ng 1(-1). No photosynthetic stress was detected in seagrass in this study during low river flow. However, with moderate river flow events, nearshore seagrasses are at risk of being exposed to concentrations of herbicides that are known to inhibit photosynthesis. (c) 2004 Elsevier Ltd. All rights reserved.

The positive impact of multiple sclerosis (MS) on carers: Associations between carer benefit finding and positive and negative adjustment domains

Purpose. This study examined benefit finding in MS carers including the dimensionality of benefit finding, relations between carer and care recipient benefit finding, and the effects of carer benefit finding on carer positive and negative adjustment domains. Method. A total of 267 carers and their care recipients completed questionnaires at Time 1 and 3 months later, Time 2 (n=155). Illness data were collected at Time 1, and number of problems, stress appraisal, benefit finding, negative (global distress, negative affect) and positive (life satisfaction, positive affect, dyadic adjustment) adjustment domains were measured at Time 2. Results. Qualitative data revealed seven benefit finding themes, two of which were adequately represented by the Benefit Finding Scale (BFS) [1] (Mohr et al. Health Psychology 1999; 18: 376). Factor analyses indicated two factors (Personal Growth, Family Relations Growth) which were psychometrically sound and showed differential relations with illness and adjustment domains. Although care recipients reported higher levels of benefit finding than carers, their benefit finding reports regarding personal growth were correlated. The carer BFS factors were positively related to carer and care recipient dyadic adjustment. Care recipient benefit finding was unrelated to carer adjustment domains. After controlling for the effects of demographics, care recipient characteristics, problems and appraisal, carer benefit finding was related to carer positive adjustment domains and unrelated to carer negative adjustment domains. Conclusion. Findings support the role of benefit finding in sustaining positive psychological states and the communal search for meaning within carer-care recipient dyads.

Segmented polyurethane nanocomposites: Impact of controlled particle size nanofillers on the morphological response to uniaxial deformation

A series of TPU nanocomposites were prepared by incorporating organically modified layered silicates with controlled particle size. To our knowledge, this is the first study into the effects of layered silicate diameter in polymer nanocomposites utilizing the same mineral for each size fraction. The tensile properties of these materials were found to be highly dependent upon the size of the layered silicates. A decrease in disk diameter was associated with a sharp upturn in the stress-strain curve and a pronounced increase in tensile strength. Results from SAXS/SANS experiments showed that the layered silicates did not affect the bulk TPU microphase structure and the morphological response of the host TPU to deformation or promote/hinder strain-induced soft segment crystallization. The improved tensile properties of the nanocomposites containing the smaller nanofillers resulted from the layered silicates aligning in the direction of strain and interacting with the TPU sequences via secondary bonding. This phenomenon contributes predominantly above 400% strain once the microdomain architecture has largely been disassembled. Large tactoids that are unable to align in the strain direction lead to concentrated tensile stresses between the polymer and filler, instead of desirable shear stresses, resulting in void formation and reduced tensile properties. In severe cases, such as that observed for the composite containing the largest silicate, these voids manifest visually as stress whitening.

Screening for posttraumatic stress disorder in children after accidental injury

OBJECTIVE. Children who have experienced an accidental injury are at increased risk of developing posttraumatic stress disorder. It is, therefore, essential that strategies are developed to aid in the early identification of children at risk of developing posttraumatic stress disorder symptomatology after an accident. The aim of this study was to examine the ability of the Child Trauma Screening Questionnaire to predict children at risk of developing distressing posttraumatic stress disorder symptoms 1 and 6 months after a traumatic accident. METHODS. Participants were 135 children (84 boys and 51 girls; with their parents) who were admitted to the hospital after a variety of accidents, including car- and bike-related accidents, falls, burns, dog attacks, and sporting injuries. The children completed the Child Trauma Screening Questionnaire and the Children's Impact of Events Scale within 2 weeks of the accident, and the Anxiety Disorders Interview Schedule for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Child Version, was conducted with the parents to assess full and subsyndromal posttraumatic stress disorder in their child 1 and 6 months after the accident. RESULTS. Analyses of the results revealed that the Child Trauma Screening Questionnaire correctly identified 82% of children who demonstrated distressing posttraumatic stress disorder symptoms (9% of sample) 6 months after the accident. The Child Trauma Screening Questionnaire was also able to correctly screen out 74% of children who did not demonstrate such symptoms. Furthermore, the Child Trauma Screening Questionnaire outperformed the Children's Impact of Events Scale. CONCLUSIONS. The Child Trauma Screening Questionnaire is a quick, cost-effective and valid self-report screening instrument that could be incorporated in a hospital setting to aid in the prevention of childhood posttraumatic stress disorder after accidental trauma.

Analysis of stirred mill performance using DEM simulation: Part 2 - Coherent flow structures, liner stress and wear, mixing and transport

Stirred Mills are becoming increasingly used for fine and ultra-fine grinding. This technology is still poorly understood when used in the mineral processing context. This makes process optimisation of such devices problematic. 3D DEM simulations of the flow of grinding media in pilot scale tower mills and pin mills are carried out in order to investigate the relative performance of these stirred mills. In the first part of this paper, media flow patterns and energy absorption rates and distributions were analysed to provide a good understanding of the media flow and the collisional environment in these mills. In this second part we analyse steady state coherent flow structures, liner stress and wear by impact and abrasion. We also examine mixing and transport efficiency. Together these provide a comprehensive understanding of all the key processes operating in these mills and a clear understanding of the relative performance issues. (C) 2006 Elsevier Ltd. All rights reserved.

Some like it wet - biological characteristics underpinning tolerance of extreme water stress events in Antarctic bryophytes

Antarctic bryophyte communities presently tolerate physiological extremes in water availability, surviving both desiccation and submergence events. We investigated the relative ability of three Antarctic moss species to tolerate physiological extremes in water availability and identified physiological, morphological, and biochemical characteristics that assist species performance under such conditions. Tolerance of desiccation and submergence was investigated using chlorophyll fluorescence during a series of field- and laboratory-based water stress events. Turf water retention and degree of natural habitat submergence were determined from gametophyte shoot size and density, and delta C-13 signatures, respectively. Finally, compounds likely to assist membrane structure and function during desiccation events (fatty acids and soluble carbohydrates) were determined. The results of this study show significant differences in the performance of the three study species under contrasting water stress events. The results indicate that the three study species occupy distinctly different ecological niches with respect to water relations, and provide a physiological explanation for present species distributions. The poor tolerance of submergence seen in Ceratodon purpureus helps explain its restriction to drier sites and conversely, the low tolerance of desiccation and high tolerance of submergence displayed by the endemic Grimmia antarctici is consistent with its restriction to wet habitats. Finally the flexible response observed for Bryum pseudotriquetrum is consistent with its co-occurrence with the other two species across the bryophyte habitat spectrum. The likely effects of future climate change induced shifts in water availability are discussed with respect to future community dynamics.

The impact of spectral composition and light periodicity on the activity of two antioxidant enzymes (SOD and CAT) in the coral Favia favus

In oligotrophic waters the light spectrum is mostly blue, and therefore the physiological and biochemical responses to blue light occurring in the coral tissue and in the symbiotic algae are important. Examination of the wavelength dependence of two free radical scavenger enzyme activity revealed an increase in activity in the blue light range (440-480 nm) compared to the red (640680 nm) in the full visible light (400-700 nm) range. These data show for the first time the relationship between the action spectra of photosynthesis and the activity of two main antioxidant enzymes in the symbiotic coral Favia favus. It was found that in the animal (host) the enzyme response to the spectral distribution of light was higher than that of the zooxanthellae, probably due to accumulation of free radicals within the host tissue. Furthermore, we found that the activity of these enzymes is affected in nature by the length of the day and night, and in the laboratory, by the duration of the illumination. Changes in the pigment concentrations were also observed in response to growth under the blue region and the whole PAR spectrum, while fluorescence measurements with the fast repetition rate fluorometer (FRRF) showed a decrease in the sigma cross section and a decrease in the quantum yield also in the blue part of the spectrum. These changes of scavenger enzymes activity, pigment concentration and fluorescence yield at different light spectra are vital in acclimatization and survival of corals in shallow water environments with high light radiation. (c) 2005 Elsevier B.V. All rights reserved.

The psychosocial impact of caregiving on young people who have a parent with an illness or disability: Comparisons between young caregivers and noncaregivers

Objective: To investigate the psychosocial impact of young caregiving by empirically validating prominent qualitative themes.. This was achieved through developing an inventory called the Young Caregiver of Parents Inventory (YCOPI) designed to assess these themes and by comparing young caregivers and noncaregivers. Method: Two hundred forty-five participants between 10 and 25 years completed questionnaires: 100 young caregivers and 145 noncaregivers. In addition to the YCOPI, the following variables were measured: demographics, caregiving context, social support, appraisal, coping strategies, and adjustment (health, life satisfaction, distress, positive affect). Results: Eight reliable factors emerged from the YCOPI that described the diverse impacts of caregiving and reflected the key themes reported in prior research. The factors were related to most caregiving context variables and theoretically relevant stress and coping variables. Compared with noncaregivers, young caregivers reported higher levels of young caregiving impact, less reliance on problem-solving coping, and higher somatization and lower life satisfaction. Conclusions: Findings delineate key impacts of young caregiving and highlight the importance of ensuring that measures used in research on young caregivers are sensitive to issues pertinent to this population.

Perceptions of organizational change: A stress and coping perspective

Few organizational change studies identify the aspects of change that are salient to individuals and that influence well-being. The authors identified three distinct change characteristics: the frequency, impact and planning of change. R. S. Lazarus and S. Folkman's (1984) cognitive phenomenological model of stress and coping was used to propose ways that these change characteristics influence individuals' appraisal of the uncertainty associated with change, and, ultimately, job satisfaction and turnover intentions. Results of a repeated cross-sectional study that collected individuals' perceptions of change one month prior to employee attitudes in consecutive years indicated that while the three change perceptions were moderately to strongly intercorrelated, the change perceptions displayed differential relationships with outcomes. Discussion focuses on the importance of systematically considering individuals' subjective experience of change.