Genetic and environmental sources of covariance between reading tests used in neuropsychological assessment and IQ subtests

In this study, we examined genetic and environmental influences on covariation among two reading tests used in neuropsychological assessment (Cambridge Contextual Reading Test [CCRT], [Beardsall, L., and Huppert, F. A. ( 1994). J. Clin. Exp. Neuropsychol. 16: 232 - 242], Schonell Graded Word Reading Test [SGWRT], [ Schonell, F. J., and Schonell, P. E. ( 1960). Diagnostic and attainment testing. Edinburgh: Oliver and Boyd.]) and among a selection of IQ subtests from the Multidimensional Aptitude Battery (MAB), [Jackson, D. N. (1984). Multidimensional aptitude battery, Ontario: Research Psychologists Press.] and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) [Wechsler, D. (1981). Manual for the Wechsler Adult Intelligence Scale-Revised (WAIS-R). San Antonio: The Psychological Corporation]. Participants were 225 monozygotic and 275 dizygotic twin pairs aged from 15 years to 18 years ( mean, 16 years). For Verbal IQ subtests, phenotypic correlations with the reading tests ranged from 0.44 to 0.65. For Performance IQ subtests, phenotypic correlations with the reading tests ranged from 0.23 to 0.34. Results of Structural Equation Modeling (SEM) supported a model with one genetic General factor and three genetic group factors ( Verbal, Performance, Reading). Reading performance was influenced by the genetic General factor ( accounting for 13% and 20% of the variance for the CCRT and SGWRT, respectively), the genetic Verbal factor ( explaining 17% and 19% of variance for the CCRT and SGWRT), and the genetic Reading factor ( explaining 21% of the variance for both the CCRT and SGWRT). A common environment factor accounted for 25% and 14% of the CCRT and SGWRT variance, respectively. Genetic influences accounted for more than half of the phenotypic covariance between the reading tests and each of the IQ subtests. The heritabilities of the CCRT and SGWRT were 0.54 and 0.65, respectively. Observable covariance between reading assessments used by neuropsychologists to estimate IQ and IQ subtests appears to be largely due to genetic effects.

Conceptual Frameworks for SIA Revisited: a cumulative effects study on lead contamination and economic change

This article trials three conceptual frameworks on an Australian case study of a small remote city suffering lead contamination, with cumulative effects from concurrent economic change due to downsizing in the mining industry. It interprets the usefulness of these frameworks, and explores two questions: can they apply to circumstances other than project assessment, and what are their relative merits as guides to SIA? All the frameworks reviewed can be used in non-project and cumulative SIA, although, if they had been used to predict the impacts in our case study, we may easily have been misled as to the resilience of the community. Choosing among these frameworks becomes a matter personal preference: each has different merits.

Assessing the seasonal influence of sewage and agricultural nutrient inputs in a subtropical river estuary

A combination of physical and chemical measurements and biological indicators identified nutrient impacts throughout an Australian subtropical river estuary. This was a balance of sewage inputs in the lower river and agricultural inputs in the mid-upper river, the combined influence being greater in the wet season due to greater agricultural surface runoff. Field sampling in the region was conducted at 6 sites within the river, over 5 surveys to encapsulate both wet and dry seasonal effects. Parameters assessed were tissue nitrogen (N) contents and delta(15)N signatures of mangroves and macroalgae, phytoplankton nutrient addition bioassays, and standard physical and chemical variables. Strong spatial (within river) and temporal (seasonal) variability was observed in all parameters. Poorest water quality was detected in the middle (agricultural) region of the river in the wet season, attributable to large diffuse inputs in this region. Water quality towards the river mouth remained constant irrespective of season due to strong oceanic flushing. Mangrove and macroalgal tissue delta(15)N and %N proved a successful combination for discerning sewage and agricultural inputs. Elevated delta(15)N and %N represented sewage inputs, whereas low delta(15)N and elevated %N was indicative of agricultural inputs. Phytoplankton bioassays found the system to be primarily responsive to nutrient additions in the warmer wet season, with negligible responses observed in the cooler dry season. These results indicate that the Tweed River is sensitive to the different anthropogenic activities in its catchment and that each activity has a unique influence on receiving water quality.

Assessing the influence and distribution of shrimp pond effluent in a tidal mangrove creek in north-east Australia

Effluent from a land based shrimp farm was detected in a receiving creek as changes in physical, chemical and biological parameters. The extent and severity of these changes depended on farm operations. This assessment was conducted at three different stages of shrimp-pond maturity, including (1) when the ponds were empty, (2) full and (3) being harvested. Methods for assessing farm effluent in receiving waters included physical/chemical analyses of the water column, phytoplankton bioassays and nitrogen isotope signatures of marine flora. Comparisons were made with an adjacent creek that served as the farms intake creek and did not directly receive effluent. Physical/chemical parameters identified distinct changes in the receiving creek with respect to farm operations. Elevated water column NH4+ (18.5+/-8.0 muM) and chlorophyll a concentrations (5.5+/-1.9 mug/l) were measured when the farm was in operation, in contrast to when the farm was inactive (1.3+/-0.3 muM and 1.2+/-0.6 mug/l, respectively). At all times, physically chemical parameters at the mouth of the effluent creek, were equivalent to control values, indicating effluent was contained within the effluent-receiving creek. However, elevated delta(15)N signatures of mangroves (up to similar to8parts per thousand) and macroalgae (up to similar to5parts per thousand) indicated a broader influence of shrimp farm effluent, extending to the lower regions of the farms intake creek. Bioassays at upstream sites close to the location of farm effluent discharge indicated that phytoplankton at these sites did not respond to further nutrient additions, however downstream sites showed large growth responses. This suggested that further nutrient loading from the shrimp farm, resulting in greater nutrient dispersal, will increase the extent of phytoplankton blooms downstream from the site of effluent discharge. When shrimp ponds were empty water quality in the effluent and intake creeks was comparable. This indicated that observed elevated nutrient and phytoplankton concentrations were directly attributable to farm operations. (C) 2003 Elsevier Ltd. All rights reserved.

Climate change manipulations show Antarctic flora is more strongly affected by elevated nutrients than water

Climate change is expected to affect the high latitudes first and most severely, rendering Antarctica one of the most significant baseline environments for the study of global climate change. The indirect effects of climate warming, including changes to the availability of key environmental resources, such as water and nutrients, are likely to have a greater impact upon continental Antarctic terrestrial ecosystems than the effects of fluctuations in temperature alone. To investigate the likely impacts of a wetter climate on Antarctic terrestrial communities a multiseason, manipulative field experiment was conducted in the floristically important Windmill Islands region of East Antarctica. Four cryptogamic communities (pure bryophyte, moribund bryophyte, crustose and fructicose lichen-dominated) received increased water and/or nutrient additions over two consecutive summer seasons. The increased water approximated an 18% increase in snow melt days (0.2 degrees C increase in temperature), while the nutrient addition of 3.5g Nm(-2) yr(-1) was within the range of soil N in the vicinity. A range of physiological and biochemical measurements were conducted in order to quantify the community response. While an overall increase in productivity in response to water and nutrient additions was observed, productivity appeared to respond more strongly to nutrient additions than to water additions. Pure bryophyte communities, and lichen communities dominated by the genus Usnea, showed stronger positive responses to nutrient additions, identifying some communities that may be better able to adapt and prosper under the ameliorating conditions associated with a warmer, wetter future climate. Under such a climate, productivity is overall likely to increase but some cryptogamic communities are likely to thrive more than others. Regeneration of moribund bryophytes appears likely only if a future moisture regime creates consistently moist conditions.

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.

Introducing evidence-based family assessment and therapy in child and youth mental health services: Applying systemic principles to maintain, sustain and build capacity

The purpose of this article is to overview the context of the mental health service in which we work, and family therapy's status prior to and after the impact of changes wrought by the introduction of the National Mental Health Policy. We then explore some key issues that we think contribute to the persistence of the occlusion of family therapy in child psychiatric services; and the strategies that we developed and are continuing to develop to support change, finally, we describe the use of a family assessment instrument that we believe is central to our change strategy.